224. EIGHTEENTH CENTURY. PT. Hi. 



CHAPTER XXV1T. 



SCIENCE OF THE EIGHTEENTH CENTURY (CONTINUED). 



Birth of Modern Chemistry Black Bergmann Cavendish Priestley 

 Scheele Rutherford Lavoisier French School of Chemistry. 



DURING the last half of the eighteenth century, while Hunter 

 and Linnaeus were adding to our knowledge of living beings, 

 and Werner and Hutton were reading the history of the 

 crust of the earth, a little group of men in England, France, 



/and Sweden were making discoveries which entirely altered 



/the science of chemistry. These men were Bergmann and 

 Scheele in Sweden ; Black, Cavendish, and Priestley in Eng- 



j land ; and Lavoisier in France. 



\ In order to understand what their discoveries were, and 

 what they taught us, it is necessary to bear in mind that up 

 to this time chemists had believed air and water to be ele- 

 ments or simple substances which could not be decomposed 

 or split up into any other kind of matter. Mayow, indeed, 

 had shown that the atmosphere could be separated into two 

 gases, but his experiments had been passed over and for- 

 gotten ; and though Dr. Hales, at the beginning of the 

 eighteenth century, had collected several gases, he had not 

 distinguished them from air. The fact was that Stahl's 

 ' phlogiston,' which was supposed to be a substance passing 



. out of burning and breathing bodies into the air, was a con- 

 Btant source of confusion, and led men away from the truth. 



